Multiplayer IF may refer to one of two things:
- An IF gaming session where a group of players share the role of the game's current PC.
- We shall dub this weak multiplayer IF or shared-PC IF.
- An IF game where two or more players adopt the roles of multiple PCs simultaneously.
- We shall dub this strong multiplayer IF or true multiplayer IF.
Weak multiplayer IF
In the most trivial case, weak multiplayer IF can be accomplished simply by having all the players together in the same room as the computer, so they can all see the screen's output at the same time, and issue suggestions to whoever's nearest the keyboard (this person may be called the "driver"). Which is fine when IF players can physically get together, but this is not always feasible.
When players aren't physically together, one needs an environment (like a mud, a forum, a chat line, etc.) where players can text chat to each other freely, and someone to act as "host" or "MC" for the session. The host runs the game on his/her/its computer, tells everyone else what the game said, and listens to the players for commands to reissue to the game.
Ideally, the host is a bot instead of an actual person. Otherwise, the host must be prepared to patiently cut and paste all the relevant text from the game to the chat environment every turn.
- ClubFloyd is a group of players that meets weekly on ifMud to play IF via the Floyd bot located in the Toyshop and Floyditorium.
- Cheeseshop (David Welbourn; 2001; JotaCode version only). The original ifMud version, written in JotaCode for ifMud, lets players share the role of the PC, a customer of the cheeseshop, without needing a "driver" or "host" as intermediaries. (Note: The Inform and TADS ports have no multiplayer features.)
- screen is a Unix program that can be used to allow players who have signed onto a Linux server to all share the same screen from a program, such as an IF interpreter. (More detail on how this is accomplished is wanted.)
- Something Awful has a forum somewhere where IF games were played. Link(s), anyone?
- if.cruels.net is a site for playing Z-code games cooperatively.
- Zinc is a Z-code and TADS interpreter written in Java, which allows for cooperative gameplay.
Strong multiplayer IF
To date, there's been very little true multiplayer IF. Some of the problems are:
- How to put IF and chat together. Wedding an IF game to any of the available chat environments is not obvious, and most authors would not want to invent their own chat systems -- just writing IF can be challenging enough!
- Multiple output text streams. True multiplayer IF must display different text to different players. They shouldn't all see the same thing when they're playing different characters within the game.
- Multiplayer puzzle design. Many standard IF puzzles can't be used as is in multiplayer games without inviting deadlock.
- Getting people to play it. Getting IF players together at the same time can itself be a challenge, especially when they are accustomed to playing solo.
Known multiplayer games
- "Lunatix Online" was an online multiplayer version of Lunatix: The Insanity Circle (Mike Snyder; 1999; MS-DOS). It was playable from 1999 to 2010.
- Maze of Doom II (Admiral Jota; JotaCode) is a two-player game on ifMud. One player bravely enters the maze while the other operates the maze's controls from a control room. Co-operation and much experimentation is required for a successful traversal of the maze.
- Werewolf (Evin Robertson; 1999; Z-code) is a multiplayer parlor game. Coded in Inform 6 with the multifloyd.h library extension, it is designed to be played only on ifMud via the Floyd bot. A port of the board game Sorry also uses multifloyd.
- Guncho is a mud where users can upload Inform 7 code to make a multiplayer IF environment.
- multifloyd.h by Evin Robertson is an Inform 6 library extension created for multiplayer games via ifMud's Floyd.
- Quest is known to have true multiplayer capabilities. Quest also provides a site where such games can be played via players' web browsers.
- Designing multiplayer puzzles by Jason Dyer for Renga in Blue (2005). Suggests that there are three principles of designing a good multiplayer puzzle: (1) Asymmetry: the players must not all do the same things. (2) Uniqueness: the players must have different powers or options, either temporarily or permanently. (3) Dependency: the players are dependent on each other for successfully carrying out their own task.